{"instruction": "You are an expert in named entity recognition. Please extract entities that match the schema definition from the input. Return an empty list if the entity type does not exist. Please respond in the format of a JSON string.", "schema": ["Chemical"], "input": "METHODS : Standard pattern electroretinograms ( P - ERGs ) and standard pattern visual evoked potentials ( P - VEPs ) were done in 25 eyes of 25 patients who had myopic PRK for an attempted correction between 5 . 00 and 15 . 00 diopters ( D ) ( mean 8 . 00 D ) ."}
{"Chemical": []}